Copying machine with simul-color copy function and divisional copy function

Abstract

A copying machine capable of executing a divisional copy mode (book copy mode) wherein an original of two image sides, i.e., two open-out successive pages of a book is copied separately based on one copy instruction and a simul-color copy mode wherein a copy image of two or more colors can be obtained by changing over the developing units to be used during one copying operation. To execute the simul-color copy mode, the copying machine includes a color dividing position for dividing one of image sides into a plurality of color regions. In the case where the divisional copy mode and simul-color copy mode are simultaneously designated, two image sides are separately copied, and also, one of the image sides in which the color dividing position exists is copied to obtain a multi-color copy image by the simul-color copy mode.

What is claimed is: 
     
       1. A copying machine comprising: a platen on which an original is placed;   a photosensitive member;   scanning means for scanning the original on the platen in a scanning direction to project a narrow, elongated image of the original onto the photosensitive member;   image forming means arranged around the photosensitive member and comprising a plurality of developing units, each of which containing toner of a different color;   input means for inputting an instruction to start an image forming operation;   means for establishing an area dividing position which divides a copying area on the platen into two copying areas in the scanning direction;   first mode designating means for designating a divisional copy mode in which the two copying areas divided at the area dividing position are separately and successively copied;   means for setting at least one color dividing position which divides one of the copying areas on the platen into a plurality of color regions in the scanning direction;   second mode designating means for designating a simulcolor copy mode during a copying operation in which a multi-color copy image is obtained by selectively changing over at least from a first one of the plurality of developing units to a second one of the plurality of developing units to form a plurality of regions having different color which are on opposite sides of the color dividing position; and   control means, when the first and second mode designating means simultaneously designate the divisional copy mode and the simul-color copy mode, for controlling the scanning means and the image forming means such that two copying areas specified at the area dividing position are separately copied, as well as for effecting the change-over control of the developing units during the copying operation to form the regions of different colors which are separated at the color dividing position.   
     
     
       2. A copying machine as claimed in claim 1, wherein the means for establishing the area dividing position determines the area dividing position based on a size of paper to be used and a magnification ratio to be used during the copying operation. 
     
     
       3. A copying machine as claimed in claim 2, wherein the means for setting the color dividing position includes at least one cursor movably mounted adjacent a side of the platen for movement along the scanning direction and a member for detecting the position of the cursor. 
     
     
       4. A copying machine as claimed in claim 1, wherein the control means controls a respective one of the developing units containing toner of a predetermined color such that the color dividing position is not included in a respective one of the regions having different colors. 
     
     
       5. A copying machine as claimed in claim 4, wherein the predetermined color is black. 
     
     
       6. A copying machine as claimed in claim 3, wherein the at least one cursor comprises two levers, each of which includes a magnet, and the member comprises a reed switch movably mounted for movement in the scanning direction in proximity to the magnet of each of the levers, the reed switch being operatively connected to the control means for outputting a color dividing position signal each time the reed switch passes a respective one of the levers. 
     
     
       7. A copying machine as claimed in claim 1, further comprising paper supply means for supplying sheets of paper of at least one size and transfer means for transferring sheets of paper from the supply means to the photosensitive member such that an image formed by toner supplied to the photosensitive member by the image forming means is transferred to one of the sheets of paper during the copying operation. 
     
     
       8. A copying machine as claimed in claim 1, wherein the scanning means includes a scanner movably mounted for movement in the scanning direction. 
     
     
       9. A copying machine as claimed in claim 7, wherein the control means effects the change-over control of the developing units by operating the first and second developing units simultaneously during the copying operation. 
     
     
       10. A copying machine as claimed in claim 9, wherein the control means prevents operation of one of the developing units when the image formed by toner of one color from the one developing units reaches a position corresponding to the color dividing position at which another one of the developing units supplies toner of a color different from the one color to the sheet of paper during the copying operation. 
     
     
       11. A copying machine as claimed in claim 9, wherein the photosensitive member comprises a photosensitive drum rotatably mounted for movement of a surface of the drum in a circular path, the first developing unit being disposed at a first position along the path and the second developing unit being disposed at a second position along the path downstream of the first position, the control means preventing operation of the first developing unit for a predetermined amount of time while the scanning means projects a first part of the image of the original on the photosensitive drum and then operating the first and second developing units simultaneously while the scanning means projects a second part of the image of the original on the photosensitive drum, the second part of the image being downstream from the first part of the image with respect to the scanning direction. 
     
     
       12. A copying machine as claimed in claim 1, wherein each of the developing units includes toner indicating means for indicating to the control means the color of the toner contained therein. 
     
     
       13. A copying machine as claimed in claim 1, wherein each of the developing units includes a magnetic brush means for supplying toner to the photosensitive member, the magnetic brush means including a magnet roller having at least one magnet pole, the magnet roller being rotatably mounted such that the magnet pole is movable from a first position facing the photosensitive member to a second position away from the photosensitive member, the magnetic brush means further including driving means operatively connected to the control means for selectively moving the magnet pole to the first and second positions. 
     
     
       14. A copying machine as claimed in claim 13, wherein the driving means comprises a lever connected to the magnet roller and a solenoid having a movable plunger connected to the lever at a position spaced from a position at which the magnet roller is connected to the lever, whereby movement of the plunger effects rotation of the magnet roller. 
     
     
       15. A copying machine as claimed in claim 3, wherein the at least one cursor comprises two cursors, each of which is movably mounted adjacent a side of the platen for movement along the scanning direction, the member detecting the position of each of the cursors.